The document FR-A-2 621 375 describes a sealed-fixing device including a rigid supporting ring suitable for being seal-stored in the cell flange so as to instal in the latter the interchangeable member which is mounted on this supporting ring. The accidental pulling away of the supporting ring bearing the interchangeable member is prevented by a safety ring cooperating with the supporting ring and the cell flange by means of two bayonet links.
The advantage of a fixing device designed as above is that the axial force needing to be exerted on the ring bearing the interchangeable member, both so as to place it in the cell flange and drive it in, is much less than that of a fixing device in which the axial hold of the ring supporting the interchangeable member in the cell flange is fully borne by this ring. The tooling allowing for these manoeuvres may thus be relatively simple and can be controlled manually.
However, in the device described in the document FR-A-2 621 375, the supporting ring may rotate with respect to the cell flange resulting in the unlocking of either of the bayonet links and thus risk pulling away the supporting ring bearing the interchangeable member under the effect, for example, of the pressure difference normally existing between the inside and outside of the containment chamber.
In addition, it is sometimes desirable that the interchangeable member secured to the cell flange be placed in a precise angular position with respect to this cell flange, this requirement not being guaranteed in the device described in the document FR-A-2 621 375.